At a glance
999 Third Ave is a 1,323,055-square-foot office building at 999 3RD AVE in Seattle, Washington, built in 1983. In its 2025 Seattle benchmarking disclosure it reported an ENERGY STAR score of 88 out of 100 (grade A), a site energy-use intensity of 30.6 kBtu/ft² and 185 tCO₂e of greenhouse-gas emissions. That score is higher than 63% of the 378 scored office buildings in Seattle.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 88 (band A) |
| Site EUI | 30.6 kBtu/ft² |
| Source EUI | 85.8 kBtu/ft² |
| GHG emissions | 185 tCO₂e |
| GHG intensity | 0.2 kgCO₂e/ft² |
| Electricity | 9,389,714 kWh |
| Gross floor area | 1,323,055 sq ft |
| Source record | seattle:345:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | 88 | +2 | 30.6 kBtu/ft² | 185 tCO₂e |
| 2024 | 86 | +1 | 30.1 kBtu/ft² | 190 tCO₂e |
| 2023 | 85 | +6 | 31.1 kBtu/ft² | 196 tCO₂e |
| 2022 | 79 | -5 | 34.6 kBtu/ft² | 219 tCO₂e |
| 2021 | 84 | -4 | 31.2 kBtu/ft² | 197 tCO₂e |
| 2020 | 88 | -4 | 30.3 kBtu/ft² | 191 tCO₂e |
| 2019 | 92 | +4 | 35.7 kBtu/ft² | 226 tCO₂e |
| 2018 | 88 | -6 | 39.8 kBtu/ft² | 251 tCO₂e |
| 2017 | 94 | ±0 | 43.1 kBtu/ft² | 279 tCO₂e |
| 2016 | 94 | +1 | 41.0 kBtu/ft² | 267 tCO₂e |
| 2015 | 93 | 43.0 kBtu/ft² | 269 tCO₂e |
Compliance context
Seattle Energy Benchmarking Ordinance (SMC 22.920)
Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
Ownership
No owning organisation shown. Names of private individuals in the disclosure are not published here.
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Location
- Address
- 999 3RD AVE
- City
- Seattle
- State
- Washington
- ZIP
- 98104
- Coordinates
- 47.60505, -122.33427
Within ~1 km
Nearby benchmarked buildings
- Columbia Centerscore 90
Office · 1,952,220 sq ft
- Seattle Convention Centerscore —
Convention Center · 1,842,925 sq ft
- Two Union Squarescore 96
Office · 1,605,578 sq ft
- Russell Investments Centerscore 92
Office · 1,592,914 sq ft
- Us Bank Centerscore 87
Office · 1,536,606 sq ft
Office · 1,527,817 sq ft
See also: most efficient in Seattle · biggest emitters
How does 999 Third Ave compare with other office buildings in Seattle?
The latest disclosures cover 497 office buildings in Seattle, out of 3,871 buildings citywide. 999 Third Ave's ENERGY STAR score of 88 compares with an average of 76 across the 378 that report a score; it scores higher than 63% of them and lower than 33%. Its site EUI of 30.6 kBtu/ft² is about 32% below the average of 44.8 kBtu/ft² — it uses less energy per square foot than the typical building in that group. Its emissions intensity of 0.2 kgCO₂e/ft² is about 74% below the group average of 0.7 kgCO₂e/ft².
At 1,323,055 sq ft, it is about 573% above the average floor area of 196,452 sq ft for those buildings. It was built in 1983, 18 years later than the group's average year built (1965). Across all 24 jurisdictions BuildingCensus covers, the 15,264 office buildings average an ENERGY STAR score of 73 and a site EUI of 59.3 kBtu/ft².
How has 999 Third Ave's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for 999 Third Ave, covering report years 2015–2025. Its ENERGY STAR score went from 93 in 2015 to 88 in 2025 (-5 points); its best year on file was 2016, at 94. Site EUI moved from 43.0 kBtu/ft² (2015) to 30.6 kBtu/ft² (2025), a 29% decrease. Reported emissions went from 269 tCO₂e to 185 tCO₂e over the same span (down 31%).
What does an ENERGY STAR score of 88 mean?
ENERGY STAR scores run from 1 to 100 and are computed by the EPA's Portfolio Manager as a percentile against similar buildings nationwide, adjusted for climate, size and use: a score of 88 means the building performs better than about 88% of its national peers. BuildingCensus bands the score into report-card grades; 88 falls in band A — high performer (85–100). Scores of 75 or higher meet the threshold for ENERGY STAR certification; certification itself is a separate, verified application that the disclosure does not record. In Seattle, 69% of scored buildings are at 75 or above.
Site energy-use intensity (EUI) is the energy a building uses on site in a year divided by its floor area, in thousand Btu per square foot — lower is more efficient. 999 Third Ave's 30.6 kBtu/ft² across 1,323,055 sq ft works out to about 40.5 billion Btu (11,865 MWh-equivalent) in 2025. Its source EUI of 85.8 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 9,389,714 kWh of electricity for the year.
Which law requires 999 Third Ave to report its energy use?
999 Third Ave reports under the Seattle Energy Benchmarking Ordinance (SMC 22.920), the legal basis of Seattle's Building Energy Benchmarking program, which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2025 disclosure (source record seattle:345:2025). Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
More office buildings in Seattle
- Troy Block (Amazon)· 1,261,155 sq ft · score 88 (A)
- Bank Of America Fifth Avenue Plaza· 1,249,055 sq ft · score 90 (A)
- Safeco Plaza / 1001 Fourth Avenue· 1,123,435 sq ft · score 80 (B)
- Fourth & Madison ( Idx Tower)· 1,052,469 sq ft · score 81 (B)
- Madison Center· 990,000 sq ft · score 93 (A)
- 333 Dexter Ave N· 934,154 sq ft · score 84 (B)
- Office buildings in Seattle· 497 benchmarked
- All Seattle benchmarked buildings· Seattle Energy Benchmarking Ordinance (SMC 22.920)
- Most efficient large buildings in Seattle
- Least efficient large buildings in Seattle
- Biggest emitters in Seattle
Frequently asked questions
What is 999 Third Ave's energy grade?
999 Third Ave scores 88 out of 100 on ENERGY STAR — band A, high performer (85–100) — in its 2025 Seattle disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does 999 Third Ave use?
Its 2025 site energy-use intensity was 30.6 kBtu/ft² (85.8 kBtu/ft² source) across 1,323,055 sq ft, including 9,389,714 kWh of electricity.
What are 999 Third Ave's carbon emissions?
999 Third Ave reported 185 tCO₂e of greenhouse-gas emissions (0.2 kgCO₂e/ft²) for 2025.
Where is 999 Third Ave?
999 Third Ave is at 999 3RD AVE, in Seattle, Washington 98104. Its coordinates are 47.60505, -122.33427 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is 999 Third Ave and when was it built?
999 Third Ave has 1,323,055 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 1983 as its year built. It is classed as office.
Is 999 Third Ave covered by the Seattle Energy Benchmarking Ordinance (SMC 22.920)?
Yes — it appears in the 2025 Building Energy Benchmarking disclosure, which lists the buildings reporting under the Seattle Energy Benchmarking Ordinance (SMC 22.920).
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About this data
Source: Building Energy Benchmarking (Seattle Energy Benchmarking Ordinance (SMC 22.920)), as published October 2, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “999 Third Ave, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/999-third-ave-aad80c3c (data as of October 2, 2026).